Language Package

	java lang basics
	String
	String Length String Concatenation charAt() getChars() getBytes() toCharArray() equals() equalsIgnoreCase() startsWith() endsWith() compareTo() substring() concat() replace() trim()
	Stringbuffer
	setLength() setChars() charAt() getChars() append() insert() reverse() delete() deleteCharAt() compareTo() substring() replace()
	Thread
	start() suspend() resume() wait() sleep() join() alive() isalive() yield() setPriority() getPriority() synchronization()
	Wrapper Class
	String Tokenizer

Lang Package - Wrapper Class

Wrapper Class:
Wrapper is nothing but, Interface between primitive data types and Address mode. Its called Wrapper Class.
Wrapper classes are classes that allow primitive types to be accessed as objects. Wrapper class is wrapper around a primitive data type.

Following table lists the primitive types and the corresponding wrapper classes:

Primitive	Wrapper
Boolean	java.lang.Boolean
Byte	java.lang.Byte
Char	java.lang.Character
double	java.lang.Double
Float	java.lang.Float
Int	java.lang.Integer
Long	java.lang.Long
Short	java.lang.Short
Void	java.lang.Void

one for each primitive type: Boolean, Byte, Character, Double, Float, Integer, Long, and Short

Byte, Double, Float, Integer and Short extend the abstract Number class

all are public final ie cannot be extended

get around limitations of primitive types

allow objects to be created from primitive types

all the classes have two constructor forms

all, except Character, have a valueOf(String s) method which is equivalent to new Type(String s)
all have a typeValue() method which returns the value of the object as it's primitive type. These are all abstract methods defined in Number and overridden in each class

  »  public byte byteValue()
  »  public short shortValue()
  »  public int intValue()
  »  public long longValue()
  »  public float floatValue()
  »  public double doubleValue()

all the classes override equals(), hashCode() and toString() in Object
  »  equals() returns true if the values of the compared objects are the same
  »  hashCode() returns the same hashcode for objects of the same type having the same value
  »  toString() returns the string representation of the objects value

getType() returns an int that defines a character's Unicode type Integer, Short, Byte and Long
all have parseType methods eg parseInt(), parseShort(), etc that take a String and parse it into the appropriate type
the Integer and Long classes also have the static methods toBinaryString(), toOctalString() and toHexString() which take an integer value and convert it to the appropriate String representation

Float and Double:

both classes have static fields which define POSITIVE_INFINITY, NEGATIVE_INFINITY, and and the following methods to test a value

-> public boolean isNan()
-> public static boolean isNaN(type value)
-> public boolean isInfinite()
-> public static boolean isInfinite(type value)

Float also has a constructor that takes a double value
both classes have methods to convert a value into a bit pattern or vice versa

-> public static int floatToIntBits(float value)
-> public static float intBitsToFloat(int bits)
-> public static long doubleToLongBits(double value)
-> public static double longBitsToDouble(long bits)